Yes or No Oracle two moon blocks, the way a Chinese temple asks its gods

Each block has a flat face and a rounded one. Taipei's Xingtian Temple, which belongs to Guan Yu, calls the flat face yang, "facing up," and the rounded face yin, "facing down," and it describes a block as shaped like a crescent moon, made of bamboo, wood or plastic, always in a matched pair. A pair can land three ways, and each way has a name.

How to ask, step by step

1. Hold the pair in your palms, flat sides together. Xingtian likens the shape to a butterfly.
2. Introduce yourself: your name, your age and your address. At a temple you say it to the god; here, say it quietly to yourself.
3. State one matter, briefly, phrased so that yes or no is a complete answer.
4. Pause to let the god consider, then raise the blocks to your brow and let them fall.
5. Read how they land and follow the rule below: three holy cups in a row for a yes, an angry cup for a no, a laughing cup to rephrase and start over.
6. Once you have your answer, leave that matter alone for a while before asking it again.

How many holy cups make a yes

There is no single rulebook, which is the first thing to know. Temples set their own customs and post them for visitors, and they disagree in exactly one interesting place: how many holy cups make a yes.

The careful answer is three. The Mazu temple at Donghai, in Taitung, sets out its procedure step by step and says one holy cup or three are both acceptable, but that as a principle it recommends three in a row, to be sure of the goddess's meaning. That is what the oracle on this page does:

1. Throw once. A holy cup counts one, and you throw again.
2. Three holy cups in a row is a yes.
3. An angry cup at any point is a no, and it cancels any holy cups that came before it.
4. A laughing cup at any point is no answer at all. Put the question more plainly and start again from the first throw, because the three have to be consecutive.

The exception is Xingtian itself. Its instructions say the first throw decides: there is no need to throw again and again until a holy cup turns up, which it calls both disrespectful to the god and a good way to get yourself worked up, and the same question should wait a while before it is asked again. If you want to ask the Xingtian way, take the first throw above and stop there.

Everybody agrees about the preliminaries. Xingtian's are steps two and three above. Donghai adds your zodiac sign and your birth date, saying whether it is a lunar or a solar date. The Ministry of Culture's reference entry adds a small gesture: pass the blocks in a few clockwise circles over the incense burner before you throw. If this sounds like filling in a form, it is. Chinese gods hold offices, and a petition to an office starts with who is asking.

The laughing cup deserves its own note, because it is the best thing in the system. Xingtian's explanation is that the question was unclear. Then it adds, with some candor, that people who ask when they already know the moment is wrong, or who have made up their minds and are asking anyway, also tend to get the laughing cup.

Here is the arithmetic the temples do not print. If each block were a fair coin, a holy cup would come up half the time, since one flat and one round can happen two ways, and the laughing and angry cups a quarter each. Three holy cups in a row would come up one time in eight.

Real blocks are not coins. The only measured figures we could find come from an entry in Taiwan's 50th national science fair, in which four eighth-graders from Nantou County threw pairs of blocks 3,031 times, across five kinds of block and three drop heights. They got 49.3% holy cups, 27.6% laughing and 23.1% angry. The rounded face, they noticed, behaves like the bottom of a roly-poly toy: a block that lands on it rocks and settles, so the flat face ends up on top a little more than half the time. It is a school project, with a hundred throws in each cell of its tables, and we treat it as one careful measurement rather than the last word.

So that is the model. Each block lands flat side up 52.3 percent of the time, on its own, which is the rate that best fits those throws. Your browser draws each block from its cryptographic random number generator, the source it uses for encryption keys, so nobody, including us, can lean on a throw.

Which is the quiet effect of asking for three. A single holy cup is close to a coin toss. Three in a row happens about one time in eight, and the single most likely end to the whole ritual is not yes or no but a laughing cup telling you to try again. The temples give their reason as being sure of the god's meaning; the arithmetic is ours, and it says the rule makes a yes hard to come by.

One twelfth-century ruler understood the odds better than most. The official History of Jin records that Prince Hailing of the Jin once stopped at a shrine at Liaoshigang and threw the blocks with a prayer: if I have the mandate of heaven, let this throw be auspicious. It was. He threw again, adding that if things turned out as promised the god would be rewarded, and if not he would tear the shrine down. Auspicious again. In 1153, now emperor, he made the god a king. Two holy cups in a row come up about one time in four, and the god, to be fair, was under some pressure. A later historian, retelling the story in the Xu Zizhi Tongjian, was less charmed: the ruler, he wrote, was using the gods to cover a murder, which is how Hailing had come to the throne.

Search for an oracle yes or no and most of what comes back is one of three things: a coin flip in costume, a Magic 8 Ball, or a tarot card read as yes or no. None of them knows the future, and neither do the blocks. What differs is how hard each one makes a yes, and whether it can decline to answer.

A coin and a Magic 8 Ball say yes half the time. The blocks, asked the careful way, say yes to about one question in eight, roughly 4 times rarer, and that is the point of three in a row: a yes has to survive three throws. Tarot has no fixed yes-or-no rule at all, so its odds are whatever the reader's convention makes them. And only the blocks have an answer that means the question is the problem. The Magic 8 Ball's noncommittal answers say "ask again later"; the laughing cup says ask it better.

The blocks are older than any temple that uses them now, and the best account of them was written by a Song-dynasty scholar who could not resist a word puzzle. Cheng Dachang, in his twelfth-century notebook Yanfanlu, explains that people putting a question to a god used to take two clam shells, toss them into the air, and read whether they landed facing up or facing down. Later the shells gave way to bamboo or wood, shaved into the shape of a clam and split in two. The name, he says, comes in two halves as well: bei, cup, because a clam shell is hollow and holds things like a cup, and jiao, which he argues was first written as the word for teaching, because the way the halves face is what the god is teaching you.

He traced the practice further back, to the Jingchu Suishi Ji, a sixth-century record of the festival year in central China, where people at the autumn sacrifice to the earth god threw the blocks to foretell next year's harvest. A note on that text, as Cheng quotes it, says the blocks were made of paulownia wood in the shape of a small clam, and that the throw with one half up and one half down was the auspicious one. That is the holy cup, written down some fourteen hundred years ago, and it has not changed since.

The poet Han Yu met the blocks in the autumn of 805, on his way home from exile in the south. At the temple on Mount Heng, he writes, the old temple keeper, who could read the god's wishes, put the blocks in his hands, showed him how to throw, and told him the result was the most auspicious there was. Han Yu's reply, a few lines later in the same poem, is magnificently unimpressed. He has been banished to the wilds and is lucky to be alive; every hope of high office is long gone; even a god who wanted to bless him would struggle to find anything to work with.

Walk into almost any Daoist or folk temple in Taiwan and there will be several pairs of blocks on the altar table for anyone to use; the Ministry of Culture's heritage entry says so in nearly those words. They are the ordinary way to put a question to whoever the temple belongs to: Guan Yu at Xingtian, Mazu, the sea goddess, at her temples up and down the coast, the earth god at the smallest neighborhood shrines, and Yue Lao, the matchmaker, whose temple visitors open with the same name, age and address before they ask about a match.

The blocks answer yes or no. For anything longer, temples have a second instrument, and it runs on the first. Chinese fortune sticks, kau cim in Cantonese and qiu qian in Mandarin, are a cylinder of numbered bamboo sticks. You draw one, by whatever method you are used to, though the Donghai temple asks you not to shake the cylinder too hard. The number leads to a verse, and the verse is the answer.

But the stick is not yours until the blocks say so. At Donghai you lay it on the altar and throw to ask whether it is the right one. A holy cup confirms it (one or three, with three recommended), a laughing cup means throw again, and an angry cup means set that stick aside and draw another. The Mazu temple at Lukang is stricter: a laughing or an angry cup there sends you straight back to the cylinder. Only then do you take the number to the counter and collect the printed verse, and the temple keeps a book of explanations, or a person, to help you read it.

This is why a fortune-stick number means little on its own. It points into one temple's set of verses, and sets are not the same everywhere, so a number without its temple is half an answer. The oracle above does the part that needs no book: the yes or the no.